O10-4 Blood fatty acid and phospholipase A2 concentrations as indicators of abnormal phospholipid metabolism in autism

Aggregation-inhibiting protein (AIP: Curtis & Greaves, 1965), which diminishes the adhesiveness of cells, particularly at low temperatures, is identified in the present paper as phospholipase A2 (EC. 3.1.1.4). Our reasons for this identification are because phospholipase activity parallels AIP activity on cell adhesion, and because various inhibitors and sera act in a parallel manner on adhesion in the presence of AIP or phospholipase. We suggest that the enzyme acts on adhesion by producing lysolecithin and other lysolipids in the plasmalemma. Addition of lysolipids diminishes cell adhesion in a manner similar to phospholipase A. Incubation of cells in Hanks' medium at 37 degrees C has a parallel effect. Conditions which would be expected to stimulate reacylation of lysolipids in the plasmalemma, i.e. incubation of cells in the external presence of CoA, ATP and a fatty acid, lead to a recovery or maintenance of adhesion after or during Hanks' incubation at 37 degrees C. All these results suggest that lipid components of the cell, probably in the plasmalemma, are of importance in adhesion. The results are discussed in relation to the long-standing controversy about the effects of low temperatures and trypsinization on cell adhesion, for phospholipase treatment of cells affects adhesion in a manner similar to trypsinization.

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Long-Chain Fatty Acid Transport at the Blood-Brain Barrier and Incorporation into Brain Phospholipids: A New In Vivo Method for Examining Neuroplasticity, and Brain Second Messenger Systems Involving Phospholipase A2 Activation

New Concepts of a Blood—Brain Barrier ◽

10.1007/978-1-4899-1054-7_13 ◽

1995 ◽

pp. 119-140 ◽

Cited By ~ 4

Author(s):

S. I. Rapoport ◽

P. J. Robinson

Keyword(s):

Fatty Acid ◽

Phospholipase A2 ◽

Blood Brain Barrier ◽

Second Messenger ◽

Chain Fatty Acid ◽

Fatty Acid Transport ◽

Acid Transport ◽

Long Chain Fatty Acid ◽

Long Chain

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Quantification of the interactions among fatty acid, lysophosphatidylcholine, calcium, dimyristoylphosphatidylcholine vesicles, and phospholipase A2

Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism ◽

10.1016/0005-2760(94)00201-9 ◽

1995 ◽

Vol 1254 (3) ◽

pp. 349-360 ◽

Cited By ~ 15

Author(s):

Elyssa D. Bent ◽

John D. Bell

Keyword(s):

Fatty Acid ◽

Phospholipase A2

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Effect of chronic ethanol administration on energy metabolism and phospholipase A2 activity in rat liver

Biochemical Journal ◽

10.1042/bj1780023 ◽

1979 ◽

Vol 178 (1) ◽

pp. 23-33 ◽

Cited By ~ 52

Author(s):

P I Spach ◽

J W Parce ◽

C C Cunningham

Keyword(s):

Fatty Acid ◽

Phospholipase A2 ◽

Phospholipid Fatty Acid ◽

Respiratory Control ◽

Liver Mitochondria ◽

Liquid Diet ◽

Male Rats ◽

Ethanol Administration ◽

Phospholipid Fatty Acid Composition ◽

Apparent Lack

1. For a period of 31 days male rats were given a liquid diet containing 36% of its energy as ethanol. Liver mitochondria from these animals demonstrated lowered respiratory control with succinate as substrate, a diminished energy-linked anilinonaphthalene-sulphonic acid fluorescence response, and lowered endogenous ATP concentrations. The phospholipid/protein ratio in mitochondria from these animals was unchanged; only minor alterations in the phospholipid fatty acid composition were observed. 2. In experiments where mitochondria were incubated at 18 degrees C in iso-osmotic sucrose (aging experiments), the above energy-linked properties were lost at an earlier time in organelles from ethanol-fed animals. Phospholipase A2 acitivty was depressed in mitochondria from control animals until respiratory control was lost and ATP was depleted. In contrast, no lag in the expression of phospholipase activity was observed in mitochondria from ethanol-fed rats. This loss of control of the phospholipase resulted in an earlier degradation of membrane phospholipids under the conditions of the aging experiments. 3. The ATPase (adenosine triphosphatase) activities, measured in freshly prepared tightly coupled mitochondria and in organelles uncoupled with carbonyl cyanide p-trifluoromethoxyphenylhydrazone, were not significantly different in ethanol-fed and liquid-diet control animals. When the mitochondria were aged at 18 degrees C, the activity increased with time of incubation in organelles from both groups of animals. A lag was observed, however, as the ATPase activity increased in control preparations. This lag was not present as APTase activity increased in mitochondria from ethanol-fed animals. 4. The significantly lowered values observed for energy-linked functions with succinate as an energy source demonstrate that ethanol elicits an alteration in liver mitochondria that affects the site II-site III regions of the oxidative-phosphorylation system. The apparent lack of control of the phospholipase A2 and ATPase activities in mitochondria from ethanol-fed animals suggests that the membrane microenvironment of these enzymes has been altered such that they can exert their catabolic effects more readily under conditions of mild perturbation. The fatty acid analyses demonstrate that the observed alterations both in the energy-linked functions and in control of the phospholipase and ATPase are not mediated through changes in the acyl chain composition of bulk-phase phospholipids.

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Effect of hypoxia on phospholipid metabolism in porcine pulmonary artery endothelial cells

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1992.262.5.l606 ◽

1992 ◽

Vol 262 (5) ◽

pp. L606-L613 ◽

Cited By ~ 4

Author(s):

G. B. Bhat ◽

E. R. Block

Keyword(s):

Endothelial Cells ◽

Fatty Acid ◽

Pulmonary Artery ◽

Fatty Acid Fraction ◽

Phospholipid Metabolism ◽

Fatty Acid Esters ◽

Hypoxic Exposure ◽

Synthetase Activity ◽

Diacylglycerol Lipase ◽

Porcine Pulmonary Artery

The effect of exposure of porcine pulmonary artery endothelial cells to hypoxic (0% O2) and normoxic (20% O2) conditions for 24 and 48 h on phospholipid metabolism was studied. Sonicates prepared from endothelial cells that were exposed to 24 h of hypoxia showed significant increases in phospholipase A1 (91%), phospholipase C (75%), and diacylglycerol lipase (57%) activities. Hypoxic exposure of cells for 48 h caused an increase in diacylglycerol lipase activity (54%) only. Hypoxia also caused significant decreases in ATP levels and ATP-dependent arachidonyl coenzyme A (CoA) synthetase activity. Phospholipase A2, lysophosphatidylcholine acyltransferase, and diacylglycerol acyltransferase activities were not influenced by 24 or 48 h of hypoxia. When endothelial cells were prelabeled with [3H]arachidonic acid and then exposed to hypoxia, increased counts were recovered from the free fatty acid fraction of medium and from the cell fatty acid esters, lysophospholipids, diacylglycerols, and triacylglycerols. There was a concomitant decreased recovery of counts from cell phospholipids. These results indicate that hypoxic exposure of endothelial cells altered phospholipid metabolism by activating deacylation pathways and inhibiting reacylation via ATP-dependent arachidonyl CoA synthetase.

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Low Temperature-Induced GA3 Sensitivity of Wheat. IV. Comparison of Low Temperature Effects on the Phospholipids of Aleurone Tissue of Dwarf and Tall Wheat

Functional Plant Biology ◽

10.1071/pp9850277 ◽

1985 ◽

Vol 12 (3) ◽

pp. 277 ◽

Cited By ~ 4

Author(s):

SP Singh ◽

LG Paleg

Keyword(s):

Fatty Acid ◽

Low Temperature ◽

Gibberellic Acid ◽

Temperature Effects ◽

Temporal Relationship ◽

Phospholipid Metabolism ◽

Isogenic Lines ◽

Receptor Sites ◽

Aleurone Tissue ◽

Close Temporal Relationship

Low temperature effects on the phospholipids of F6 Rht 3/rht 3 isogenic lines of wheat were studied. Significant low-temperature-induced (5°C) augmentation in the phospholipids of the dwarf selection were detected. More specifically, a 20 h-5°C preincubation enhanced considerably the levels of phosphatidylinositol, phosphatidylcholine and phosphatidylethanolamine in the aleurone tissue of the dwarf selection. In addition, these changes displayed a very close temporal relationship with the low- temperature-induced increase in gibberellic acid (GA3) sensitivity. In the case of the tall selection, only the imbibition of water was required to initiate the synthesis of major phospholipids of its aleurone tissue and low temperature preincubation had no effect on either the phospholipids or their fatty acid constituents. These results are discussed in the light of the hypotheses that GA3 receptor sites are membrane-based lipids and that the Rht gene causes an aberration in the phospholipid metabolism of the aleurone tissue which can be corrected by low temperature.

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Formation of Prostaglandin Cyclo-Peroxides and Prostaglandins by Phospholipase A2 in Platelets of Normal and Essential Fatty Acid Deficient Rats

10.1055/s-0039-1680762 ◽

1977 ◽

Author(s):

J.E. Vincent ◽

F.J. Zijlstra

Keyword(s):

Fatty Acid ◽

Platelet Aggregation ◽

Phospholipase A2 ◽

Essential Fatty Acid ◽

Essential Fatty Acid Deficient ◽

Incubation Periods ◽

Rat Platelets

Phospholipase A2 has a biphasic action upon rat platelet aggregation, enhancing after shorter and inhibiting after longer incubation periods. The first effect is inhibited by indomethacin.Cycloperoxides and thromboxane-like substances and prostaglandins are formed on incubation with the enzyme in the same amounts whether aggregation is induced or not. Formation of cycloperoxides and thromboxanes is not leading to aggregation. Phospholipase A2 enhances the aggregation of the platelets of essential fatty acid deficient rats. Only very small amounts of cycloperoxides and thromboxane-like substances are formed. It is concluded that cycloperoxides and thromboxanes can enhance, but not induce aggregation in rat platelets.

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